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BACKGROUND CONCENTRATION OF AIRBORNE MICROBE
IN NEW CONSTRUCTED BUILDING
AHMAD SAYUTI ZAINAL ABIDIN
A thesis submitted in
fulfillment of the requirements for the award of the
Degree of Masters of Mechanical Engineering
Faculty of Mechanical and Manufacturing Engineering
Universiti Tun Hussien Onn Malaysia
MAY 2015
iv
ABSTRACT
Exposure to indoor air pollution is now becoming serious public health problem in a
wide variety of non-industrial setting such as residences, offices, schools, hospital and
vehicles. This study investigate the level of airborne microbe in indoor environment at
three different phase of building commissioning for a new constructed building in
Bandar Baru Bangi, Selangor, Malaysia. Three phases involved is after building
devolves to building owner, during installation of furniture and one month after
building occupancies. In particular, the airborne microbes’ concentrations were
determined by using a single stage impactor (Biosampler) as per requirement of
National Institute of Occupational Safety and Health (NIOSH) method, NIOSH
Manual Analytical Method NMAM 0800. The total concentration of airborne bacteria
were average to 533, 159 and 420 CFU/m3 in the first, second and third phase. For
airborne fungi the results yield a mean concentration of 235, 98 and 101CFU/m3
respectively across the sampling phases. These findings indicated that although a new
constructed building should be having a significant background level of airborne
microbe (total bacteria count and total fungi count). The building owner should be
aware to their indoor air status to protect the occupant from the safety and health issue
in the work place especially for mechanical ventilated building.
v
ABSTRAK
Pendedahan kepada pencemaran udara dalam bangunan sekarang menjadi masalah
kesihatan awam yang serius terutamanya kepada pelbagai jenis persekitaran bukan
industri seperti kediaman, pejabat, sekolah, hospital dan kenderaan. Kajian ini
menyiasat tahap dedahan mikrob bawaan udara di persekitaran dalaman dalam tiga
peringkat pentauliahan bangunan baru yang terletak di Bandar Baru Bangi, Selangor,
Malaysia. Tiga fasa terlibat dalam pentauliahan adalah selepas penyerahan kepada
pemilik bangunan, semasa pemasangan perabot dan sebulan setelah kemasukan
penghuni. Persampelan mikrob bawaan udara telah ditentukan dengan menggunakan
impactor satu peringkat seperti keperluan kaedah National Institute of Occupational
Safety and Health, NIOSH Manual Analytical Method NMAM 0800. Jumlah purata
kepekatan bakteria bawaan udara adalah 533, 159 dan 420 CFU/m3 di fasa pertama,
kedua dan ketiga. Untuk kulat bawaan udara keputusan menghasilkan satu kepekatan
purata 235, 98 dan 101CFU/m3 masing-masing merentasi fasa-fasa persampelan.
Penemuan ini menunjukkan bahawa walaupun di dalam bangunan baru terdapat juga
kepekatan latar belakang mikrob bawaan udara (bakteria terampai diudara dan kulat
terampai diudara) yang perlu di ambil perhatian. Pemilik bangunan harus sedar kepada
status udara dalam bangunan terutamanya pengudaraan bangunan bagi tujuan untuk
melindungi penghuni dari masalah keselamatan dan kesihatan di tempat kerja.
vi
TABLE OF CONTENTS
TITLE i
DECLARATION ii
ACKNOWLEDGEMENT iii
ASTRACT iv
TABLE OF CONTENTS vi
LIST OF TABLE x
LIST OF FIGURE xii
LIST OF SYMBOLS AND ABBREVIATION xiv
LIST OF APPENDICES xv
CHAPTER 1 INTRODUCTION 1
1.1 Introduction 1
1.2 Problem Statement 1
1.3 Objective of Study 4
1.4 Scope of Study 5
1.5 Significant of the Research 6
1.5.1 Industry (employer and
employees)
6
1.5.2 Government 6
1.5.3 Education Sector 7
1.6 Limitation of the Study 8
vii
CHAPTER 2 LITERATURE REVIEW 9
2.1 Introduction 9
2.2 Airborne microbe in indoor environment 9
2.3 Building and building systems 10
2.3.1 Building physical properties 10
2.3.2 Building service systems 12
2.3.3 Building commissioning 13
2.4 Thermal environment 14
2.5 Building and occupant management 16
2.6 Legal requirement on indoor microbe 18
2.7 Assessment method for microbe sampling 20
2.7.1 Sampling equipment 21
2.7.2 Selection of sampling media 22
2.7.3 Sampling strategy 22
2.8 Summary 23
CHAPTER 3 METHODOLOGY 24
3.1 Introduction 24
3.2 Research framework 25
3.3 Study location 27
3.4 Sampling point and monitoring phases 29
3.4.1 Selection of sampling point 29
3.4.2 Selection of monitoring phases 30
3.5 Working environment microbe samplings 33
3.5.1 Sampling method 33
viii
3.5.2 Measurement of indoor bacteria and
fungi
33
3.5.3 Preparation of sampling media 38
3.5.4 Measurement of thermal environment
condition
40
3.6 Statistical analysis 40
3.6.1 Normality test 40
3.6.2 Comparison on mean 41
3.6.3 Correlation relationship 41
CHAPTER 4 RESULT AND DISCUSSION 42
4.1 Introduction 42
4.2 Measurement of TBC and TFC in new
constructed building
43
4.2.1 TBC and TFC in non-carpeted office 44
4.2.2 TBC and TFC in carpeted office 45
4.2.3 TBC and TFC in classroom 46
4.2.4 TBC and TFC in classroom corridor 47
4.2.5 Compliances of TBC and TFC against
ICOP DOSH 2010
47
4.3 Differences of TBC and TFC at different
phases of building commissioning
49
4.3.1 Differences of TBC and TFC during
building commissioning
49
4.3.1.1 Normality test 50
4.3.1.2 Mean comparison microbe 52
ix
4.3.2 Relationship between thermo
environment and airborne microbe
55
4.4 TBC and TFC comparison among different
setting
57
4.5 Summary 61
CHAPTER 5 CONCLUSION AND RECOMMENDATION 62
5.1 Introduction 62
5.2 Findings of the study 63
5.3 Recommendation 64
5.4 Conclusion 65
REFERENCES 66
APPENDICES 72
x
LIST OF TABLES
2.1 Acceptable range for specific physical parameter 15
3.1 Sampling location and number of sampling point 29
3.2 Number of sampling point at different phases of
sampling
31
4.1 Total bacteria count and total fungi count in non-
carpeted office.
44
4.2 Total bacteria count and total fungi count in
carpeted office.
45
4.3 Total bacteria count and total fungi count in
classroom
46
4.4 Total bacteria count and total fungi count in
classroom corridor
47
4.5 Compliance result on total bacteria and total
fungi concentration
48
4.6 Average count of total bacteria and total fungi at
different phases of building commissioning
49
4.7 Shapiro-Wilk analysis for TBC in ach sampling
phases
50
4.8 Shapiro-Wilk analysis for TFC in each sampling
phases
52
4.9 Kruskal-Wallis H test comparison of mean for
TBC and TFC
53
4.10 Relative humidity and temperature data and
normality result
55
4.11 Thermal environment comparison of mean
between phases
56
xi
4.12 TBC and TFC detected in non-carpeted office at
different phases
57
4.13 Airborne microbe comparison of mean between
sampling location
58
4.14 TBC and TFC detected in non-carpeted office at
different phases
58
4.15 TBC and TFC detected in carpeted office at
different phases
59
4.16 TBC and TFC detected in classroom at different
phases
60
4.17 TBC and TFC detected in classroom corridor at
different phases
60
xii
LIST OF FIGURES
3.1 Highlights the research frame work and the
expected outcome from the research
26
3.2 New constructed building in Bandar Baru
Bangi
27
3.3 Building service system at roof top 28
3.4 Sampling locations at carpeted office
a) initial phase b) during furniture
installation c) one month after occupancy.
32
3.5 Plan layout for sampling point located at
sixth floor
32
3.6 Equipment for microbe sampling (a) digital
flow calibrator, (b) single stage impactor
with 400 holes and (c) SKC Quick Take 30
33
3.7 Assembling of calibration train 34
3.8 Alcohol swap applied onto the impactor 35
3.9 Sampler location and recommended height 35
3.10 Sampling media shipment method 36
3.11 Airborne microbe sampling diagram 37
3.12 Colony counter for microbe counting 38
3.13 Flow chart for media preparation 39
3.14 IAQ meter for relative humidity and
temperature sampling
40
4.1 Airborne microbe sampling period 43
4.2 Q-Q plot for TBC in each of sampling
phases
51
xiii
4.3 TBC at different sampling phases 53
4.4 TFC at different sampling phases 54
xiv
LIST OF SYMBOL AND ABBREVIATION
CFU/m3 - Colony Forming Unit per meter squared (concentration)
DOSH - Department of Occupational Safety and Health Malaysia
IAQ - Indoor Air Quality
ICOP - Industrial Code of Practice
MEA - Malt Extract Agar
NIOSH - National Institute of Occupational Safety and Health
OC - Office Carpeted
ONC - Office Non-Carpeted
OSHA - Occupational Safety and Health Act (Act 514)
SBS - Sick Building Syndrome
SOCSO - Social Security Organization
TBC - Total Bacteria Count
TFC - Total Fungi Count
TSA - Trypticase Soy Agar
UTHM - Universiti Tun Hussein Onn Malaysia
% RH - Relative Humidity
oC - Temperature
xv
LIST OF APPENDICES
APPENDIX TITLE PAGE
A List of publications 73
B List of presentations 75
C Building layout plan sampling location 76
D List monitoring and sampling photos 83
E List of q-q plot for normality study 85
F List of raw data collected in each phases 89
CHAPTER 1
INTRODUCTION
1.1 Introduction
This chapter described the fundamental background to this research. This chapter
basically discussed problem arising from poor indoor air quality in ventilated building.
The significant of the research, scope of study and limitation of the study also been
discussed in this chapter.
1.2 Problem Statement
Exposure to indoor air pollution is now becoming serious public health problem in a
wide variety of nonindustrial setting such as residences, offices, schools, hospital and
vehicles. Convenience indoor environment expressed by safer and healthier condition
is one of the most important factors affecting the productivity today. It is noted that
people spend almost 80 to 90 percent of their time stay indoors (Wang, et al., 2001).
With the range of 10 000 to 30 000 litre of air breath by normal person, it is essential
to ensure that the air we breathe is clean from any pollutant that may harm our health.
Although Malaysia is aggressively promoting green building concept in
creating safer and healthier indoor building environment, the Social Security
Organization SOCSO data from 2006 till 2012 show that quite significant number of
industrial accident have occurred in indoor workplace environment. Indoor accident
occurs from varies source such as floor, confine quarters, stairs, other traffic and
working surfaces, environment factors such (lighting, ventilation, temperature, noise
and others IAQ parameters). The green building concept is a schematic
compliances parameter that considers a few factor such as building materials selection,
sources of outdoor contaminant and ventilation systems.
In September 2011, one government building located near Cyberjaya was
closed up to three month due to fungi growth inside their building. All the worker were
instructed to work from home as interim measure to prevent worker directly inhale
contaminated air. Overexposure of airborne microbe were also reported in April 2008,
where Hospital Sultan Ismail in Johor was closed for seventeen month due to clear
growth of microbe inside the building.
Among the indoor air pollutant identified, airborne microbe is one of the most
contaminant that addressing major issue in defining poor indoor air quality. A wide
variety of microorganism such as fungi (moulds, yeasts), bacteria, viruses, and
amoebae can be found in the indoor environment. Contamination of indoor air with
microorganisms can occur under many circumstances. Such contamination most often
occurs when a fault in the building that utilizing Heating Ventilation Air Conditioning
HVAC system, or other system that allows the germination of micro-organisms.
Inhalation of very large concentrations of fungal spores can cause
hypersensitivity pneumonitis, but this rarely results from building exposure. Chronic
exposure to most fungi can induce allergic or asthmatic reactions in humans, and a
very few species can cause diseases directly. Some moulds are toxigenic, producing
mycotoxins that often accumulate in the spores. The inhalation of spores containing
certain mycotoxins has been shown to induce many of the symptoms normally
associated with Sick Building Syndrome SBS. Other products of fungi include certain
Volatile Organic Carbon VOCs. Such compounds characterized by mouldy smells
occur only when there is active and considerable fungal growth. There is some
evidence to suggest that these can contribute to SBS. The potential of health risk
caused by the exposure to indoor air contaminant airborne microbe could produce a
significant increase of health problem to the worker especially that work in offices.
In 2005, Department of Occupational Safety and Health DOSH published a
Code of Practice of Indoor Air Quality (COP IAQ) marked as one of the first attempts
to have a legal related implication of indoor air quality in Malaysia. Later in 2010,
DOSH announced new improved legal related requirement of The Industrial Code of
Practice Indoor Air Quality ICOP IAQ 2010. Under this ICOP IAQ it stipulated
minimum standard for selected parameters that will avoid discomfort and/or adverse
3
health effect among employees and other occupant of an indoor or enclosed
environment served by a mechanical ventilation and air conditioning (MVAC) system
including air-cooled split unit. This ICOP IAQ has been drawn up to ensure employees
and building occupants are protected from poor indoor air quality that could adversely
affect their health and wellbeing, and thereby reduce their productivity. It is one of the
general duties under the Occupational Safety and Health Act 1994 (Act 514) for the
employer and an occupier (including building owner and building management) to
provide a safe workplace to their employees or other person than his employees
(occupant). The role of scientific research in distinguishing a safer indoor environment
for public health is to provide the necessary technical basis for assessing; managing
and communicating the risks furthermore contribute to increase compliances to the
related IAQ regulation.
In the recent year, many studies have been conducted about the healthfulness
of indoor air quality, including the amount of time people spend indoors and the
associated implications for indoor contributions to total exposures, the sources of
indoor air pollutant contributions to problematic indoor air quality and the increasing
number of health-related complaints related to indoor air quality.
Building materials exposed to environmental conditions and with poor
maintenance can lead to mould growth. Some materials, especially those that are
porous, are more likely than others to support microbial growth. As a result, these
materials can become potential indoor sources of bio-contaminants including mould.
Common materials susceptible to mould growth include porous materials and those
with cellulose substrates. These may include gypsum wallboard, ceiling tile, insulation,
textiles, wall coverings, floor coverings, and office panels. In some cases, materials
may be treated with anti-microbial agents as a preventive step. The ability of these
materials to support or to resist mould growth is often not well documented.
Problematic building related to indoor air quality frequently being identified
after health-related complaints been addressed or microbe growth in indoor air
environment prevailed. Reactive approaches were implemented by conducting a
thorough indoor air quality assessment resulting to a non-decisive conclusion due to
fail to identify the possible source of indoor air pollutant. Baseline data should be
measured to distinguish the possible sources of health-related complaints especially
for new constructed building. Commissioning program should take into account issues
4
related to indoor air pollutant baseline measurement in order to recognize the potential
health risk inside the building.
From above discussion, it can be seen that in order to investigate the interaction
and relationship between airborne microbe concentration and good indoor
environment, two aspects of knowledge is required. The first is to quantify the building
commissioning phases contributes to concentration of airborne microbe. The second
is to distinguish the level of compliance for airborne microbe at each phase of new
building commissioning against the ICOP IAQ 2010.
1.3 Objective of the study
The specific objectives of the study are:
i. To measure the concentration of airborne bacteria and airborne fungi in a new
constructed building during commissioning processes.
ii. To investigate the concentration of airborne bacteria and fungi in new
constructed buildings and compare with recommended acceptable exposure
limit at 500 CFU/m3 and 1000 CFU/m3 respectively.
iii. To determine whether there is differences of indoor bacteria and fungi in
different phase of new building commissioning (after building devolve to
building owner, during installation of furniture and one month after building
occupancies).
5
1.4 Scope of the study
NIOSH new constructed buildings was selected for this research for it nature of typical
office, training and research centre. There was a new building selected in the research;
which located in Bandar Baru Bangi, Selangor, Malaysia named as Menara NIOSH in
this study.
i. Since the buildings located in Malaysia with typical a Mechanical
Ventilation Air Conditioning MVAC system, it represents the normal
setting of Malaysian building. Now days, the new constructed building
in Malaysia is equipped with this MVAC system as an alternative in
overcoming the issue of hot and humid condition in this region.
ii. Different phase of building commissioning program in this research
normally is similar with others; i.e building devolved to building owner,
furniture instalment and one year warranty after occupancy. Data
gathered in this research in some way can be generalized with the other
Malaysian building, which has similar setting with NIOSH new
constructed building.
iii. Even though microbe in indoor environment covers a wide variety of
family, such as mites, protozoa, fungi, bacteria, and dander; this research
however focus only on total bacteria and total fungi. Bacteria and fungi
are studied due to their established available method and data based on
previous studies. The concentrations of airborne microbe are represents
by total number of bacteria and fungi colonies count in sampling media.
The thermal environment parameters that were covered are relative
humidity and temperature.
6
1.5 Significant of the study
The study to determine the background level of airborne microbe in new buildings can
be an informative data to enhance the industries and government knowledge regarding
indoor air quality and to provide scientific data for future research for education sector
as well.
1.5.1 Industry (employer and employees)
Some related industries would benefit from the outcome of the study. The employers’
awareness will increase in establishing good practice of IAQ in terms of monitoring
the work environment. At the same time the employer would comply with section 15,
Occupational Safety and Health Act 1994. Also the outcome of the study would
influence on the workers’ productivity.
The direct impact to employees is conducive work environment. The guideline
that will be developed will be able to monitor the building performance and at the same
time will be able to analyse the data to ensure the adequate ventilation provided to the
workers and protect the workers from adverse health problems. The traditional
technique used in industrial hygiene will be improved and more monitoring process
will became easier.
1.5.2 Government
The government will get direct benefit from this study. As the awareness from the
industries increases, it will become easier to establish the occupational safety and
health policy as required in section 16, OSHA that is the duty to formulate safety and
health policy. The government also would be able to reduce the amount of insurance
claimed through SOCSO, and this savings can be allocated to the other sectors for
economic development. With this allocation, the government can produce and place
emphasis on foreign direct investment (FDI) to Malaysia. At the same time, the
government can benefit through the available established Malaysian Standard. These
standards provide guidelines to the employer to develop their capabilities on ensuring
they follow the Malaysian Standard for their competitiveness in borderless world and
global market. Malaysia through government agencies like the Department of
7
Occupational Safety and Health (DOSH) will be able to compile relevant data and it
can be a resource in developing the regulation and enforcement activities. This study
is needed to provide national data related to airborne microbe in indoor air and may
provide general overview of Malaysian offices. Early indication of microbe
contamination in new constructed building is essential and in conjunction with the
establishment of Malaysian Industrial Code of Practice Indoor Air Quality ICOP IAQ
2010; to promote healthy working lifestyle among Malaysian citizen.
1.5.3 Education sector
Education and training sector can benefit from the study through the guideline
developed. The system will become the starting point to the other researches that are
related with the working environment. Through the guideline development, the
training agency such as National Institute of Occupational Safety and Health (NIOSH)
can take advantages from the system to improve the course curricula that have been
developed. The training will be conducted internally or externally (abroad). From the
outcome of this study, the guidelines on IAQ commissioning and maintenance in new
building will be established. The technique on data capture and analysis will become
more appropriate due to working environment quality improvement.
8
1.6 Limitation of the study
The studies are limited to the activities involved in new constructed building. The
buildings that involved in this study were owned by National Institute of Occupational
Safety and Health (NIOSH), Malaysia. Nevertheless, the implementation proposed
solution depends on company’s willingness to deploy the solution. Moreover, the
research work has no direct access and authority to enforce the proposed solution to
the company even though the case study was carried out at the designated buildings.
For this study, the building was selected due to availability of new building. The nature
of the study is on safety and health enhancements in the working environment, the
development process and the related activities like data collection in selected buildings.
The stages that were involved in the building occupancy were before, during furniture
and fitting install and one month after occupancy. The key point is to monitor the
airborne microbe in the working environment that includes total bacteria and total
fungi that posed health effects. The predicted result is based on the sampling and
testing of air quality parameters within the nominated premises at the specified
sampling times. The level of contaminant may be different depend on the weather
condition or the level of activity of the occupants in the building.
CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
In this chapter, the relevant literature is reviewed. As the scope of study is at the new
constructed building, building properties are discussed in section 2.3 which mainly
touch about the building properties and building commissioning process. Thermal
environment factors that become one of the contributors of microbe growth are
reviewed in section 2.4.The overview of management of occupant and building itself
are discussed in section 2.5. The legal requirement pertaining to acceptable limits for
indoor airborne microorganism are reviewed in section 2.6.
2.2 Airborne microbe in indoor environment
Exposure to indoor air pollution is now becoming serious public health problem in a
wide variety of nonindustrial setting such as residences, offices, schools, hospital and
vehicles. Increasing concern regarding this issue is due to most people spending their
working time in indoor environment. Among the indoor air pollutant identified,
airborne microbe is one of the most contaminant that addressing major issue in
defining poor indoor air quality. Bacteria and fungi are most commonly
microorganisms associated with indoor air quality complaint and most often
implicated as indoor bio contaminants (Wong et al., 2009). Microbial amplification
that occurs in the indoor environment can become source of exposure to the occupants
especially when the organisms and/ or their by-products are released into the air as
bioaerosols (Wong et al., 2009).
10
Discussion regarding airborne microbe contamination in indoor environment
frequently associated with four main issues. The factors involved is building and
building systems, building and occupant management, thermal environment and legal
requirement.
At the beginning of this chapter, researcher is focusing on the component
involved in constructing a building. As enveloped building serve the purpose of
sheltering and providing safer work place, deeper review concerning about the material
selection during building construction discussed, services systems used inside a
building also been argued. The researcher also review the importance of building
commissioning stage that contributes to variation of microorganism in indoor
environment.
Enclosed building frequently associated with indoor thermal comfort. Issue
arising from uncontrolled thermo environment might lead to divisive complaint. A part
of being a contributing factors that support the proliferation and growth of bioaerosol
in the indoor air, it is also known to effect the productivity of building occupant.
Therefore the relationship between building and occupant management was also
discussed in detail in this chapter to connect the contributing factor. Fourth factor
discussed in details is the legal framework pertaining to airborne microbe in indoor
environment.
2.3 Building and building systems
One of the main purpose of building is to protect human against outdoors environment
condition such as exposure to sun, rain, hot and humid air or other external influences
that might harm human health. Comfort and convenience indoor building environment
often being major issue affecting occupant productivity as it serves as decisive factors
for the quality and value of the building.
2.3.1 Building physical properties
Normally, a building is consisting of building physical properties such as building
envelop system and building ventilation system such as MVAC system. Building
physical properties often refer to the element of building that involved in heat transfers
process including exterior building envelop, internal element and internal heat sources.
11
The building envelops functioning as thermal bridge connecting indoor environment
with outdoor climate through heat transfer across the building envelop. Selection of
building material is essential to construct building wall, floors and roofs because a
good building material shall react to protect the exterior and interior of a building
against unnecessary weather violent. The study on effect of building material is quite
extensive.
Pastuszka, et al. (2000) carried out a study to determine the sources of indoor
air microbes and reported that building including the frame, finishing material, and
ventilation system is one of the contributors of higher concentration of airborne
microbe in indoor environment. Pessi, et al. (2002) in their study about outbreaks of
microbes from external walls into the indoor environment found that bio
contamination originating from the envelope of precast concrete panel buildings in a
subarctic climate was rare. They also raise, deterioration of building frame may subject
to high count of microbe. Thus, the sources of bio contamination from the building
envelope should not be ignored due to it will contribute to the total airborne microbe
count during sampling.
Vacher, et al. (2010) carried out a study to determine the impact of paint and
wall paper on fungal growth in plasterboard and aluminium reported that at relative
humidity near 95%, a non-biodegradable material like aluminium support the fungal
growth after it was covered with biodegradable material such as paint or wall paper.
This finding indicates that in indoor environment there is a higher chance of
microorganism growth especially building with high moisture content. As mentioned
above the selection of building material is essential to prevent any catalysing factor
that can boost the growth of microorganism in indoor environment.
Studies have demonstrated that even at the clean room there were a significant
number of airborne microorganisms found (Favero, et al., 1966). Existence of mouldy
partition or decomposed wall frequently becomes first choice indicator of problematic
indoor environment related to biological exposure especially in the office (Wong et al.,
2008). Biological contaminants are often found in areas that provide food and
moisture or water. Bedding, carpet, wood material, furniture stuffing and other areas
where dust collects may accumulate biological contaminants. In particular, activities
like talking, sneezing, coughing, walking, washing and toilet flushing can generate
airborne biological particulate matter (Gots et al,. 2003).
12
2.3.2 Building service systems
Modern building nowadays frequently equipped with building system such as Heating
Ventilation Air Conditioning HVAC system that serve as artificial ventilation to
support the movement of air inside tight building. In hot and humid country likes
Malaysia, this building system in normally known as Mechanical Ventilation and Air
Conditioning MVAC system. The purpose of MVAC is to provide thermal comfort
within the building. The amount of air conditioning load required and thus air
conditioning energy used depends very much on the air temperature maintained in the
building. Some office buildings and hotels maintain indoor temperatures as low as 18
to 20 degrees centigrade when the comfortable temperature is about 24 degrees
centigrade. There are many office buildings in Malaysia where the indoor temperature
is so low that the occupants wear sweaters at the work desk. It is obvious the owners
are no aware of the cost implications of their actions. It should also be noted that the
average outdoor air temperature in Malaysia is only about 4 degrees above the comfort
range (Chan et al. 2009)
According to the Environmental Protection Agency (EPA), the air inside the
average home is up to five times more polluted than the air outside. Results from in-
home air tests across North America support this government finding. Nearly every
home (96%) had at least one indoor air quality problem which are 86% had high levels
of particles and bioaerosols like dust, pollen and viruses and 71% were filled with
odours and potentially harmful chemicals and gases.
Kalamess et al. (2009) reported that ventilation system had greater influences
on indoor climate than building envelope fabric itself. Significant change in
temperature and relative humidity in indoor environment play an important role in
providing catalysing environment for microorganism growth. Anthony et al. (2001)
also revealed similar finding which found that office occupant might exposure to
higher concentration of microbe during the start-up of ventilation system normally in
early morning or long weekend due to such office environment would become
excellent microbe incubator.
Wong et al. (2008) in their study concluded that microbial growth did not
reveal any significant different at any time between two different office having same
thermal environment factor such as temperature and relative humidity. Yet, significant
higher level of airborne bacteria and fungi were observed in the same office when the
13
main MVAC systems were shut down. Under certain condition, airborne microbial
would be correlated with thermal environment parameter. Thus, it could be used as a
good prediction parameter to evaluate the failure rates due to excessive airborne
bacteria and fungi levels in air conditioning offices.
Li et al. (2012) in their study concluded that the supply air velocity had a great
influence on the dust distribution in ducting system, further investigation related to
microbial growth relationship and dust deposition yielded significant correlation
between those two parameter. Where microorganism counts were positively
correlated, when deposition dust increased, microorganism count could increase by
two or three times.
2.3.3 Building commissioning
After completing most construction process of a new building, contractor responsible
shall devolve the building to the building owner and they shall verify all the building
facilities including the building physical properties and building system. The process
of verifying is named building commissioning. Building commissioning is a
systematic approach to improving system performance, operation & maintenance,
indoor air quality & thermal comfort, and energy efficiency, as well as benefits like
improving occupant comfort, health & welfare, and productivity, in both new and
existing buildings (Dept of Veterans Affairs, United State 2013). This is an important
process as it assists the building owner in providing safe and healthy facilities;
optimises energy use, reduces operating cost, prevent unwanted contaminant exposure
and furthermore minimize complaint from building occupant. Generally
commissioning project shall verify the building physical properties and building
service systems. Method of commissioning can varies from one to another country
depend on the local authorities. In Malaysia, we only emphasize best practice of
building commissioning which consist of verification of building system such as
verification of ventilation system, building electrical facilities and building envelop.
One of the aspects that have been best approach in determining successful
building commissioning is to conduct baseline IAQ assessment program (Dept of
Veterans Affairs, United State 2013). IAQ assessment is carried out to identify any
possible root cause of an outbreak harmful contaminant in ventilated building. There
is two cluster of parameter been assess during the assessment (DOSH ICOP IAQ 2010).
14
First cluster is physical parameter consist of temperature, relative humidity and air
movement. Second cluster is indoor air contaminants consist of chemical and
biological contaminant and ventilation performance indicator. Chemical contaminant
is assessed by measuring the level Carbon Monoxide, Formaldehyde, Ozone,
respirable particulates and Total volatile organic compound (TVOC) in indoor
environment. Biological contaminant which consists of total bacteria and total fungi
count are sampled during the assessment. In order to verify the effective of ventilation
performance, Carbon dioxide is measured at each of ventilation pathway.
2.4 Thermal environment
The occupational hazards associated with indoor air quality (IAQ) are recent
phenomenon, being related in many cases to buildings that were constructed with
centralize Mechanical Ventilation Air Conditioning MVAC systems. Acceptable
range for human comfort is 19-25 oC. Outside this range human tend to feel either hot
or cool (Dobney and Sinclair 1995). Most air conditioning system is therefore designed
to maintain temperature within the range of 20-24 oC.
Issue pertaining to indoor air happen when there was an outbreak of harmful
contaminant into the indoor environment. Many factors have been identified as being
the root cause of this phenomenon, but there is no conclusive evident to support the
overall conclusion. As discussed in section 2.2.3, there is two cluster of indoor air
assessment program in determining good indoor environment condition. In this study,
researchers focus on physical and biological parameter. Studies have demonstrated
that there was significant correlation between thermal environment conditions against
indoor airborne microorganism. Microorganisms in a MVAC can lead to odours and
in some cases, disease or allergic reaction. These problems arise when the numbers of
bacteria and fungi, or viruses increase due to conditions that favour their growth (Nims
1999).
Table 2.1 below show the acceptable limit for physical parameter stipulated by
Malaysia government in order to minimise complaint related to poor IAQ.
15
Table 2.1: Acceptable range for specific physical parameter
Parameter Acceptable range
Temperature 23-26 oC
Relative humidity 40-70%
Air movement
0.15 – 0.50 m/s
The level and stability of indoor relative humidity is influenced by several factors,
such as indoor temperature, moisture sources from human presence and activity and
ventilation and infiltration air change rate and airflow in rooms. Relative humidity also
can be influenced by the release or uptake of moisture by hygroscopic surfaces of the
building fabric including the building envelope, as well as the interior walls and floors
and furniture and the absolute humidity of the outdoor air. (Kalamees, et al., 2009).
Building owners frequently conduct walkthrough observation to identify the
sources of problem as passive approaches after complaint have been made by building
occupants. Wet filters, wet ducting insulation or standing water in any part of the
system, such as condensate pans or ducts might be the early symptoms of these
microorganisms contamination in indoor environment.
Indoor air pollution results when man-made and natural chemicals, gases,
particles, and other substances are produced or released in or near the home. Common
pollutants found in buildings are volatile organic compounds, airborne microorganism,
formaldehyde, particulates, radon, asbestos, and combustion gases and by-products.
These pollutants come from a variety of sources such as household cleaning products,
wood or fuels that are burned, building materials and products, furnishings, paint
strippers, pesticides, the soil under a house, and human activities (Gots, et al., 2003).
In order to be able to reach and infect their host, the airborne pathogens need
to survive in surrounding environment, which makes factors like temperature and
relative humidity is most favourable for it to growth (Bolashikov, & Melikov, 2009).
Airborne microbe normally associated with adverse health effect but limited of
scientific evidence perhaps becomes constrains in establishing the uniform standards
for indoor ambient air in commercial and residential structure (Gots, et al., 2003).
Berent, et al. (2011) in their study found airborne bacteria were present in all
the sample site range 100 to 1000 CFU/m3. They also stated that in a storeroom
16
periodically flooded with rainwater give highest count of fungal. Significant reduction
of counted fungal were observe after departing renovation and mechanical cleaning to
the flooded building.
Sarica, et al. (2002) in their study conclude that even in the hospital there is a
significant number of microbe were detected. Using gravitational settling method they
manage to obtain significant colony of microbe in one of the crucial area in a hospital
which was in operation theatre. Micro fungi can live in extreme conditions in almost
all regions and all climates.
Tsai, et al. (2002) in their study of measuring the concentration of airborne
bacteria in 100 US office buildings found that the bacteria concentration showed more
seasonal difference, which may due to change in occupant dress and activities as well
as ventilation pattern during cooling and heating seasons. Mesophilic bacteria
comprised a larger proportion of total cultural bacteria then thermophilic bacteria.
Factor contributing to fluctuation of thermal environment condition inside building is
frequently linked to poor ventilation. A part of that, occupant movement inside
building also might contribute to these phenomena. Therefore the building and
occupant management is discussed.
2.5 Building and occupant management
A person working in enclosed environment that is depended on the condition of the
environment to stimulate their level of satisfaction. Oseland (1999) establish that there
was three main factors attribute to the level of environmental satisfactory. The first
element is environment condition such as physical condition of the building, spaces,
ergonomic and aesthetics. Second is physiology factor such as gender, age and ethnic
group. Third factor is psychology element that might influence dissatisfactory of
occupant such as personality, expectation or experiences in work.
Environment condition furthermore was divided into four main groups.
Physical condition inside a building is normally linked with their thermal environment
condition such as temperature, humidity or air flow. A part of being an influence factor
of satisfactory, thermal environment also favours the growth of microorganism in
indoor environment has been discussed before in section 2.3. Other physical condition
that might contribute to dissatisfactory is lighting or noise arising from inside or
outside the building.
17
Planning of building space is a vital step before any construction take place.
Building designer has to consider the entire attribute either exterior or interior of the
building in order to fulfil the requirement of building owner and to satisfy building
occupant. Constructions of a building often overlook the need of space for building
occupant in their design. Modification of working space after building construction
was finished might be the best solution for this issue. Tempered in original plan layout
can lead to further IAQ problem such as obstruction of air flow inside working space
or uneven air distribution from MVAC systems.
Before occupancies of any building, the building owner will install furniture
that suit the purpose of it use. Normally this phase take place after the building has
been hand over from building constructor to the building owner. Selection of material
used to construct the furniture is essential because it might be source of unwanted
contaminant in indoor environment. Matching the furniture with available spaces
inside a building is a challenging process. In order to reduce the health effect arising
from the incompatible of furniture with building occupant, the building owner have to
consider ergonomic factor of each furniture design. Work space and control ideally
have to suit broad range of occupant because they might varies depending of body
weight or height. Therefore, ergonomic factor can also contribute to building use
satisfaction.
Aesthetic factors such as colour and quality of building interior or exterior
might also influence worker productivity. There is no strong evidence to conclude such
factor can contribute to total satisfaction but it is frequently include in study about the
impact of building environment toward worker productivity (Haynes, 2008).
Often we can see potential problematic building shall face many complaints
from the building occupant. A good building management have greater influence in
occupier productivity. Less complaint also prevailed by the occupant if building owner
share any issue related to indoor building status especially related to their comfort
condition such as problematic air conditioning system or MVAC under maintenance
(Haynes, 2008). It can also be said that perception of building occupant toward
acceptable indoor condition may varies for one to another. This variation may occur
from different sources of factor such as outdoor climate, building location and building
age. The indoor thermal environment is one of the important factors in determining
level of comfort among building occupant. A majority of the research studies indicate
an average productivity loss of 10 per cent due to poor IAQ. Therefore, by improving
18
the IAQ, a conservative benefit of 6 per cent could readily be achieved (Dorgan and
Dorgan, 2005).
Poor environment condition inside a building also linked to healthy issue
among building occupant. Health effects due to indoor air pollutants may reveal an
acute effect as well as chronic effect. Acute effect or short-term problems include a
stuffy, odorous environment and symptoms such as burning eyes, skin irritation, and
headaches. Chronic effect or long-term health problems have a longer latency period.
The magnitude and duration of damaging health effects are influenced by the time of
exposure, concentration, presence of a pre-existing unhealthy condition, and age.
Health conditions involving some allergic reactions, including hypersensitivity
pneumonitis, allergic rhinitis, and some types of asthma, are triggered by bioaerosols.
Symptoms related to bioaerosols include sneezing, coughing, shortness of breath, fever,
and dizziness. Infections such as influenza, measles, and chicken pox are also
transmitted through the air. Overall, poor air quality may be responsible for a decrease
in work performance, general feeling of poor health, reduced ability to concentrate, or
illness. In many part of the world there is country that set an acceptable limit for IAQ
parameter to be complied by building owners. This is to protect both building and its
occupant from unwanted harmful contaminants. Therefore, the issue related to legal
requirement on indoor airborne microbe is discussed below.
2.6 Legal requirement on indoor microbe
The field of OSH has undergone significant change over the past two decades. Some
of the reasons include the following: technological changes that have introduced new
hazards in the workplace; proliferation of safety and health legislation and
corresponding regulation; increase pressure from regulatory agencies; realization by
executives that workers in a safe and healthy workplace are typically more productive;
increased pressure from environmental groups; corporate social responsibility and
increased pressure from labour organizations and employees in general (Goetsch,
2010).
In recent years the public have given greater attention to indoor health
associated with exposure to microbiological contaminant. Recommendation on the
allowable limit for the airborne microbe concentration in indoor air environment in
Malaysia was only addressed by the Department of Occupational Safety and Health
19
DOSH, Industrial Code of Practices for Indoor Air Quality ICOP-IAQ 2010. This
guideline was produced as reactive limits for place of works such as office building in
dealing with the microbe exposure in indoor environment.
Despite the fact that people are working and spend most of their working hours
at the workplace, little attention and resources are accorded to health and safety at
work (Leman, 2010). One way of improving health and safety issues at the workplace
is the usage of practical tools. Practical tools are means that act as guides, instruments
for developing occupational safety and health issues, in order to effect positive changes
or address a challenge. Tools that are practical and user-friendly facilitate occupational
health and safety work when addressing issues of concern. For example, these tools
can be of enormous assistance in identifying risks quickly and ensuring that they are
prevented or reduced.
This task is very challenging, in particular as the work environment and
organizations have become more complex inconsequence of globalization and
mechanization. The more mechanized a workplace is, the more challenges are to be
found in coping up with the speed of work and decision making. There are many tools
and still more to come that will empower people to be well informed and to know how
to avoid serious effect, or any effect at all, during their work life. These tools, if
properly utilized by people in the world of work, can improve the quality of life. It is
pleasing to realize that the tools and guides being developed include everything from
identification of risks, including data collection and job safety analysis, to work setting
application (Pule, 2008).
In 2010, Department of Occupational Safety and Health (DOSH) published an
Industrial Code of Practice of Indoor Air Quality (ICOP IAQ) in order to regulate
issues related to indoor air quality at the place of work especially in the offices. (DOSH,
2010). In this new revised ICOP IAQ, total bacteria and total fungi are clearly listed
as one of the compulsory parameter that need to be consider in indicating good indoor
air assessment. Acceptable limit for those total bacteria count is 500 CFU/m3 and 1000
CFU/m3 for total fungi count.
Korea is one of the leading countries when discussing issues related to IAQ
assessment. Korean Ministry of Environment announced the Indoor Air Quality
Management Act in 2004. The act established a total airborne bacteria threshold limit
value of 800 CFU/m3 for hospital, kinder garden, senior care centre and postpartum
nursing centre.
20
Ki Youn Kim and Chi Nyon Kim (2007) in their study on airborne
microbiological characteristic in public building of Korea including hospital, childcare
center, elderly welfare facility and maternity recuperation centre found that mean
concentration of total bacteria did not exceed the Threshold Limit Value TLV
800cfu/m3. Concentration for total fungi range from 300 to 600 CFU/m3. The level of
airborne bacteria and fungi was highest in childcare centre and the lowest in elderly
welfare facilities, which could explain by the different of resident activities. The
dominant genera identified in the public buildings were Staphylococcus spp.,
Micrococcus spp., Corynebacterium spp., and Bacillus spp., for airborne bacteria and
Penecillium spp., Cladosporium spp., and Aspergillus spp., for airborne fungi
respectively.
Among South East Asia region, Singapore is the only country that have a clear
guidelines for good indoor air quality in office building. The guideline was established
in October 1996 to complement the engineering specification set out by the Singapore
Guideline for Good Indoor Air Quality in Office Premises (SS. CP 13). According to
this guideline, recommended maximum concentration for total bacteria and total fungi
is at 500 CFU/m3. Thermal environmental parameters such as relative humidity is
limited to not more than 70 percent with temperature setting range between 22.5 to
25.5 degree Celsius (Institute of Environment Epidemiology, 1996)
2.7 Assessment method for microbe sampling
The assessment conducted is carried out during normal business activity and has taken
into consideration the following the sources of indoor air contaminants an occupant’s
exposure to environmental tobacco smoke, an occupant’s exposure to air contaminants,
either from indoor or outdoor sources, the prescribed activities, the adequacy of
mechanical ventilation at the place of work and the necessary actions to be taken to
improve the indoor air quality at the place of work.
Further elaboration regarding method for microbe sampling is discussed in this section.
Basically, this discussion is divided into three main topics which consist of selection
sampling equipment, preparation of sampling media and sampling strategy.
21
2.7.1 Sampling equipment
Determination of airborne microbe in indoor environment often requires reliable
devices. Reliable sampling device normally linked with uninterrupted sampling flow
across sampling period. Several sampling device are available commercially such as
the Anderson single stage impactor, Burkard portable air sampler, Reuter Centrifugal
Sampler (RCS) and Surface Air System (SAS) Super 90. (Metha et al. 1996).
Differences of each sampling device is based on its principle of operation. In their
researcher, they concluded that Burkard sampler would be the best substitute sampling
device if Anderson sampler is not available. In this study, researcher is using the
Anderson with single impactor as sampling devices. Selection of sampling devices is
referred to sampling method used in this study and previous study that often use similar
sampling device to collect airborne microbe (Law et al. 2001, Kim et al. 2007) This
selection is also based on the availability of equipment to conduct the assessment.
Tsai et al. (2002) in their study of measuring the concentration of airborne
bacteria in 100 US office buildings using single stage impactor Anderson sampler with
a sampling period of two minutes and flow rate of 28.3±1.4 L/min manage to isolate
5201 of bacteria colonies. Since the aim of the study is focus on bacteria concentration
not the identification, single stage impactor is adequate to meet the objective.
Lis et al. (2004) in their study conducted in Poland confirmed that municipal
landfill sites were serious source of airborne bacteria and fungi that could deteriorate
the microbiological air quality in buildings located in its sites. Six stage Anderson
impactor (model no 10-710: Graseby Anderson, Atlanta, Ga.) was used since their
objective of study is to identify the genera of airborne bacteria and fungi. The sampler
separates particles by aerodynamic diameters into six fractions that impact onto the
surface of the agar plates. Each of the fractions (>7, 7.0-4.7, 4.7-3.3, 3.3-2.1, 2.1-1.1,
1.1-0.65 µm) relates to the determined part of the human respiratory system. The
‘respiratory fraction’ (particles smaller than 5 µm) is able to penetrate into the alveoli.
Similar sampling trains were used by Law et al. (2001) when the researcher tried to
study the microorganism profile characteristics in office building in Hong Kong. The
researcher are using spot sampling or one replicate sampling as their strategy of
sampling referred to the outcome of preliminary study which the researcher found that
there was no significant difference among triplicate samples.
22
2.7.2 Selection of sampling media
Ren et al. (2001) in their study to evaluate the reliability of prediction made with
questionnaire to predict the household aeroallergen exposure levels found that there
was only a very weak relationship between the house characteristic, as described by
questionnaire, and the presence of fungal propagules in indoor air. They also found
that the number of CFU/m3 air collected on indistinctive agar shall produce significant
different value of colonies count. In their study, they found that MEA generate
significantly higher colonies count than on DG-18 with a mean of 1033.5 and 846.0
CFU/m3 respectively.
Singh (2001) in his review paper stated that Dichloran Glycerol (DG18) agar
is excellent to be used as sampling media for selected airborne fungal such as
Aspergillus, Penicillium and Wallemiaspp as well as other xerophiles. MEA and DG18
yield a better count of fungal for a common species found in indoor air. Wan-Keun Jo
and Young-Jun Seo (2005) also using the same sampling media to collect airborne
fungal due to it selectivity. They also refer to Ren et al. (2001) in determining the
appropriate sampling media for fungal sampling.
Sampling media that is frequently used to sample for airborne bacteria is
Trypticase Soy Agar TSA (Hussin et al. 2011). According to SKC operating manual
(2000), it is also suggested to use TSA for sampling or airborne bacteria.
2.7.3 Sampling strategy
Airborne microbe sampling is essential in this study. Therefore, selection of
sampling strategy is vital otherwise it will reflect a non-decisive conclusion of research.
The selection of sampling location is recommended to be representing the primary
workstation. Placing a sampling location as near as possible to the workstation is
advisable as this can stimulate the real time exposure of microbe to the building
occupants. Interruption of sampling point by work activities should be avoided.
Location of the building system such as air supplier diffusers, induction units, floor
fan should also be identified prior to selecting sampling point (DOSH ICOP IAQ 2010).
By identifying the possible pathway of microbe entering the indoor environment this
can help to minimize any cross contamination during airborne microbe sampling. As
23
discussed before in section 2.2 and 2.4, building and it occupant is named to cause
higher concentration of airborne microbe in indoor environment.
It is important to acknowledge any possible sources of error during sampling.
Berent et al. (2011) in their study found airborne bacteria were present in all the sample
site range 100 to 1000 CFU/m3. Sampling conducted using six stages Grase by
Anderson impactor with 28.3 l/min flow rate at a height of 1.0 to 1.5 meter from the
floor to stimulate human breathing zone. The applied sampling time was 5 minute for
both bacteria and fungi.
Dols et al. (1994) applied ‘spot’ measurement that provides one-time value of
the measured parameters in their research. In his study, he tried to develop an indoor
air quality commissioning program in new office building in United State by
measuring IAQ pollutants such as carbon monoxide, carbon dioxide, formaldehyde,
particulates, radon, volatile organic compounds and thermal comfort parameter consist
of temperature, relative humidity and operative temperature. The research was
conducted in ten stories building in United State and he found that all the IAQ pollutant
and thermal comfort parameter were below the ASHRAE references value.
2.8 Summary
In this chapter, the past research and the literature review on present of microbe in
indoor air environment, effect of thermal environment condition with microbe growth,
legal requirement on indoor microbe and assessment method for microbe sampling
discussed. The IAQ assessment as a tool was clearly identified. The indoor air
monitoring and assessment development was considered. The variation monitoring
system from past research and the research gap were highlighted.
CHAPTER 3
METHODOLOGY
3.1 Introduction
This chapter describes the research method that is central to this thesis. This chapter
briefly discussed the method used to obtain required data regarding on the Indoor Air
Quality assessment in the building commissioning and maintenance phases for safety
and health enhancement and sustainable work environment. The sampling method and
approach is discussed that includes the strategies for selection and point of interest in
conducting monitoring. Also an explanation on why the case study method was chosen
and how it was applied including system development, selection of area for this study,
data that was gathered, analysis of the data covers the details of the subjects in this
study such as pollutants and study locations. Where and how the information was
obtained is also discussed.
66
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